Art of thermal insulation



R. H. MCKE'E ART 0F THERMAL INSULATION Filed Aug. 19. 1929 .....OW'O0.50.

June 27, 1933.

Patented Jansz?, 1933 the same. I

MLPHEIcIEEOFJEBBEYCITY,mJEBSEY ABT 0l' THERMAL INSULATION Applicationiled August 19, 1939. Serial lo. 887,021.

The present invention 'relates to the art of thermal insulation and moreparticularly to a thermal insulator and a process of making Heretoforemany ty es of insulators have been proposed and use in apparatus such asice-boxes, refrigerating systems and the like for retaining the coldwithin the ice-box and keeping the heat from the surroundin 15 vironmentfrom enterin ellthe interior o the box. Among the materials previouslyused may be mentioned cork board, cork dust, cotton batting, etc. Thesematerials have many disadvantages but one of 15 advantages is that whenAthey are placed in the wall of a refrigerator such as a refrigeratorfreight car, storehouse or even a housel hold refrigerator,

insulating material 2 to changes in tem pheric pressure. and the thespace filled with the breathes in and out due rature and in atmosoistair goes in the space moisture condenses on the cold surfaces so thatonly dry air is exhaled from the said ace.

u in the Due to this condensation within'sulated space a collection ofmoisture takes place within the It is commonly known that suchapproximately 20% first three months after ating walls: decrease ininsulation value the w attempts have been made to remedy theshortcomings of prior insulating materials but none as far as I amaware, has provided the art with an economical, practical, 4andsatisfactory a6.

I have material for commercial purposes.

discovered a thermal insulator for cold systems which is free from theobjections of prior factured au practical scale.

materials and which can be manuand used on an economical and In additionmy invention has the obiact of providin the art with an extremelycellular cracked.

ght

structure It1 is also within the contemplainsulator w 'ch has a porousand which self-heals, if

*5 tion of myiinvention to-provide an insulator which does not breathetween' the walls of a refrigerator can and sealed hermetically.advantages of the inventiomwill completely objects and W become apparentso that a space bebe filled Other from the following 'descripthe maindisinstallation. Many g1' tion in conjunction with the accompanylngdrawing, in which:

Fig. lis a front elevation of a refrigerator door embodying myinvention, parts being broken away for purposes of clarity; and

Fig. 2 is a sectional view on the line 2--2 of bustible under 300 undsof pressure, considera le quantities o these 1 :A: are dissolved in themolten pitch. ith higher pressure more gas is dissolved. The resultingsolution o gas in the molten pitch can be run into a container where thedissolved gas will be 'released and a porous cellular mass of excellentinsulating material is produced. The specilic gravit of these porouspitch insulating structures been found to vary from 0.50 to 0.75 whereasthe s ic avities of the original pitches varie from 1.15 to 1.80.

The solution of the gas in the molten pitch is not instantaneous and itwas found that a period of from one to two hours of contact of the gasunder pressure with the pitch is a satisfactor eriod of time. The longerthe o time the more nearly complete saturation of the molten pitchl withgas is achieved.

When the pressure on the gas-is increased,

more will be dissolved and more cells will su uently be formed in themass of material. The greater the number of cells saturate liberatloting a gas can be mixed with the molten pitch and then heated to liberategas which Will blow up the mass of pitch. For instance, sodiumbicarbonate or ammonium sesquicarbonate can be mixed with molten itchand then heated somewhat to drive ofi) the gas from the carbonates. Ofcourse, other compounds readily evolving a gas can serve in place of thecarbonates but sodium bicarbonate is one of the best as well as one ofthe cheapest salts to use for this purpose.

Since my improved insulating material can be melted very easily, it canbe poured into the Wall of a refrigerator and allowed to solidify. Thepoured insulator when set and hardened is a desirable, efficient andinexpensive insulator for refrigerating systems and the like.

In any cases where it is desirable and appropriate ground cork, pumicestone or similar substances can be mixed with molten pitch and then themixture treated with gas as described hereinabove.

When it is desired to obtain an insulator with a large amount of gasmaintained therein, the walls of the container or the like can bechilled with cold Water. For instance, the door of a householdrefrigerator is made of steel and has a filling opening in the uppercorner or at one side. Molten pitch carrying the dissolved gas is runthrough the opening into the interior of the door and the escaping gasmakes the mass porous and cellular so that the interior of the door isfilled with nl v improved porous, insulating material. If it isdesirable to retain more gas in the insulating mass, the outside of thesteel door can be chilled with running water or can be dipped in a Waterbath. In either event the poured insulator will contain more gas than ifno chilling were used. The opening in the door may be left Without anyspecial cover or may be covered and ainted after the molten pitch hassolidified? In the handling of my improved material, the pouredinsulator may be made in the place where it is required or the materialcan be made in one place and shipped to the point of use. In thepreferred method of carrying out the last mentioned procedure, pitch ismelted in a shipping container and gas under pressure is iun `in untilthe required amount of gas has been dissolved in the pitch. The gaspressure is maintained on the molten pitch while the latter issolidifying in the container. The solidified pitch can be shipped in thecontainer and, when required for use, can be heated up to the meltingpoint. This molten mass can then be poured into the walled space to befilled with the insulating material and on pouring, it becomes porous.

Another use of my improved insulating material is for insertion into theWall of a house by pouring the material between parts of the wall. Forthis purpose there is best introduced a considerable proportion ofinorganic porous material like granular pumice stone or pieces of lowdensity porous gypsum.

My improved insulating material can be used in conjunction with Walledspaces or chambers of various types. In the present instances. arefrigerator door embodying the invention will be described andillustrated merely by way of a typical example.

Re erring more particularly to Fig. 1, the numeral 1 designates thefront Wall of a refrigerator door of a household refrigerator, forinstance. The front face is usually plain and is provided with hingesand a handle which are so Well known that they have not beenillustrated.

0n the rear face of Wall l a casing or linin 2 which is preferably7 madeof metal, is a lxed by suitable means such as Welding, screws, bolts,rivets, or other appropriate means. The casing may have any suitableshape but I prefer to employ a rectangular configuration with slopingsides 3. In the present instance, the rear face of Wall 1 constitutesthe hack portion of the casing, although it is to be understood that theback portion can be made integral with the front and side Walls of thecasing.

An opening 4 of, say, rectangular cross section is provided on the topside of the casing through which the latter may be filled with my newinsulating material. After the casing is filled, the opening may bepainted or otherwise closed to finish of'rl the top in a. smooth andattractive manner.

Surrounding the sides yof the casing and aliixcd to the rear4 face ofWall 1 is a plurality of strips 5 of a cushioning material such asrubber. Wood, or the like. These strips insure a tight joint between theinside of the door and its frame in the refrigerator when the door is ina closed condition.

The procedure involved in filling the casing of the refrigerator doorwith my improved insulating material is obvious to those skilled in theart. A mass of my material is heated sufficiently to convert it into aHuid condition or state so that it can flow or can be poured readily andconveniently from a container. W'hen the material is in this condition.it is poured into the casing until the latter is preferably completelyfilled. Upon cooling and setting, the insulating material will seal theinterior of the casing hermetically and will prevent air from passinginto and out of the casing with the deposition of moisture. In otherWords the objectionable process of breathing referred to hereinabove iseliminated and all of the disadvantages incident thereto are eliminated.

It is to be noted that due to the self-heating nature of my newinsulating material, a walled space or chamber can be maintained in asealed condition permanently because the material heals any cracks orfissures or the like which may tend to develop due to shocks, han ing,etc.

It is to be further noted that the resence of carbon dioxide bubbleswill ten to render the insulating material non-iniammable.

I claim 1. A thermal insulator comprising a poured non-water absorbinnon-brittle, plastic cohesive pitch materia having a porous, cellularstructure containing a non-combustible gas and having the property ofselfhealing. t

2. A thermal insulator comprising a substantially homogeneous mass ofnon-brittle, plastic, cohesive pitch containing a multilicity of cellsimprisoning a non-combustible gas and incapable of breathing in a walledspace, said pitch being capable of selfhealing. v

3. A thermal insulator for cold systems comprising a mass ofnon-brittle, plastic, cohesive pitch of a porous and cellular structurehaving a non-combustible carbon-cow taining as enclosed within saidstructure, said pitc bein capable of self-healing.

4. A therma insulator for cold systems comprising a mass of non-brittle,plastic, co-

hesive pitch of a porous and cellular structure having carbon dioxidegas incorporated in said mass of itch, said pitch being capable ofself-he ing.

5. A walled s ace containing a mass of non-brittle, plastic, cohesivepitch having a multiplicity of cells impriscnm a non-combustible asincorporated therein, the said pitch sea ing the said space hermeticalland preventing breathing and being capa le of self-healing.

6. A refrigerator door having a lining oon- 4 hand.

RALPH H. MCKEE.

crailrlcua or CORRECTION.

Patent Nor 1.915. 940.

June 27, 1933.

RALPH H. McKEE.

It vis hereby certifiedthat error appears in the printed Vs|recificatuinof the ,above numbered .patent requiring correction aa followaz. Page 2,line 126, for

"estiment-read "self-heal'f; and that with thia'correction therein that.Athe same may case in the .Patent Office.

the said lettera Patent ahould be read conform to the `record of theSigned and aealed'thia l24th `day of October,y A. D. 1.933;

(Seal) l l?. M. Hopkins ActinaGcmminimr of fiamma like which may tend todevelop due to shocks, han ing, etc.

It is to be further noted that the resence of carbon dioxide bubbleswill ten to render the insulating material non-iniammable.

I claim 1. A thermal insulator comprising a poured non-water absorbinnon-brittle, plastic cohesive pitch materia having a porous, cellularstructure containing a non-combustible gas and having the property ofselfhealing. t

2. A thermal insulator comprising a substantially homogeneous mass ofnon-brittle, plastic, cohesive pitch containing a multilicity of cellsimprisoning a non-combustible gas and incapable of breathing in a walledspace, said pitch being capable of selfhealing. v

3. A thermal insulator for cold systems comprising a mass ofnon-brittle, plastic, cohesive pitch of a porous and cellular structurehaving a non-combustible carbon-cow taining as enclosed within saidstructure, said pitc bein capable of self-healing.

4. A therma insulator for cold systems comprising a mass of non-brittle,plastic, co-

hesive pitch of a porous and cellular structure having carbon dioxidegas incorporated in said mass of itch, said pitch being capable ofself-he ing.

5. A walled s ace containing a mass of non-brittle, plastic, cohesivepitch having a multiplicity of cells impriscnm a non-combustible asincorporated therein, the said pitch sea ing the said space hermeticalland preventing breathing and being capa le of self-healing.

6. A refrigerator door having a lining oon- 4 hand.

RALPH H. MCKEE.

crailrlcua or CORRECTION.

Patent Nor 1.915. 940.

June 27, 1933.

RALPH H. McKEE.

It vis hereby certifiedthat error appears in the printed Vs|recificatuinof the ,above numbered .patent requiring correction aa followaz. Page 2,line 126, for

"estiment-read "self-heal'f; and that with thia'correction therein that.Athe same may case in the .Patent Office.

the said lettera Patent ahould be read conform to the `record of theSigned and aealed'thia l24th `day of October,y A. D. 1.933;

(Seal) l l?. M. Hopkins ActinaGcmminimr of fiamma

